I wonder where he learned it from, but these days, Calder would sometimes stretch out both arms (think Titanic) when walking. Last Tuesday, he did just that when he was walking across the platform of Kovan mrt. The platform happened to be empty except for a Secondary school girl. I think what she saw was this tall youth with arms strangely outstretched swooping down towards her (he must have been curious and wanted a closer look at something she had). And she cowered in bewilderment. So Calder swooped towards her and veered off as he walked on. I was rather far behind (because Calder walks much faster than me) but near enough to witness this amusing scenario. Ethel told me, when I related the incident, that I should have explained that Calder is autistic. That's true. The girl must have thought she met a weirdo.